Perhaps solar superflares contributed to the emergence of life on Earth

Representation of a solar superflare (Image NASA's Goddard Space Flight Center, Greenbelt, Md.)
Representation of a solar superflare (Image NASA’s Goddard Space Flight Center, Greenbelt, Md.)

An article published in the journal “Nature Geoscience” describes a study on the relationship between super solar flares of a few billion years ago and the emergence of life forms on Earth. According to a team of NASA scientists led by Vladimir Airapetian those gigantic storms provided the energy needed to warm up the Earth and to trigger some chemical reactions needed to form complex molecules such as RNA and DNA on which life is based.

The Sun became brighter with the passage of time and when it and the Earth were young the planet was receiving about 70% of solar energy it receives today. When this characteristic of the young Sun was discovered, it created a problem because in that condition the Earth was supposed to be a snowball while there are geological evidence that water was liquid.

This apparent inconsistency is called the faint young Sun paradox and this new research could solve it. The key to finding the solution was studying stars similar to the Sun in order to understand its history. The required data arrived from the archive of the observations made by NASA’s Kepler space telescope. Among the stars observed there are some similar to the Sun but with an age of just a few million years.

The data collected by Kepler shows that in these young stars particularly intense coronal mass ejections are common. These particularly violent phenomena, called in jargon superflares, now are rare on the Sun, in the order of about one per century. The Kepler data show that on young stars there can be up to ten superflares a day.

To understand what were the conditions in that distant time we must keep in mind the fact that the Earth was very different as well. The planet’s atmosphere was formed for about 90% by nitrogen molecules (N2) that got broken by the energy charged particles coming from the Sun.

This phenomenon occurred because then the Earth’s magnetic field was weaker than today so many more particles from the Sun could get through it. The consequence was that nitrogen atoms could in turn break carbon dioxide molecules and combine with the liberated oxygen. The nitrous oxide generated was a much more potent greenhouse gas than carbon dioxide and allowed to retain more heat in Earth’s atmosphere.

In this process hydrocyanic acid was also created which perhaps provided nitrogen for the formation of organic molecules such as amino acids. As a result, it’s possible that the energy from superflares contributed in various ways to create the conditions for the development of life on Earth. This study involved scientists working in various fields and will help to better understand the origins of life on Earth but also the search for other planets that could harbor life forms similar to ours.

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